GS1881, GS4881, GS4981 Monolithic Video Sync Separators Features Description noise tolerant odd/even flag, back porch and The GS1881, GS4881 and GS4981 are general purpose sync horizontal sync pulse separators for use in a wide variety of video applications. The devices extract the timing information from composite fast recovery from impulse noise video signals with scan rates from 15 to 130kHz. excellent temperature stability The GS1881 is a drop-in replacement for the industry 0.5V to 4Vpp input signal amplitude with 5V supply standard LM1881 with much improved performance. The well-controlled clamp discharge current and slicing device generates composite sync, vertical sync, back porch level and odd/even field signals. The GS4881 is identical to the programmable horizontal scan rate (up to 130kHz) GS1881 but features a noise immune back porch pulse composite, vertical, back porch, odd/even (GS1881, which maintains a constant H rate during the vertical GS4881), horizontal (GS4981) outputs interval. The GS4981 is identical to the GS4881, except that it provides horizontal sync in place of the odd/even output. predictable vertical output pulse width with default trigger for non-standard video signals All three devices feature a self-adjusting windowing circuit Pb-free and Green for noise immunity, which synchronizes to H rate. This windowing circuit determines the odd or even field in the 5V to 12V supply voltage range GS1881 and GS4881, gates the back porch pulse in the pin compatible with LM1881 sync separator GS4881 and GS4981, and generates the horizontal sync output in the GS4981. Application Selection Chart The devices feature an improved input stage which ensures that the input signal is sliced at a predictable point due to Application Choose Device: well-controlled input clamp discharge current and sync slicing level. A missing pulse detector enables the devices Direct LM1881 Replacement with GS1881 to recover quickly from impulse noise disturbances by Improved Performance temporarily increasing the clamp discharge current by New Applications Substitution for GS4881 roughly ten times. The input stage will operate with signals LM1881 from 0.5 to 4Vp-p with a 5V supply. New Applications Requiring Horizontal GS4981 Sync Output The GS1881, GS4881 and GS4981 also feature a predictable vertical output pulse width with a default trigger for non-standard video signals. All three are available in commercial and industrial temperature ranges and are packaged in both DIP and SOIC. GS1881, GS4881, GS4981 Monolithic Video Sync 1 of 29 www.gennum.com Separators Data Sheet Proprietary & Confidential 6926 - 5 November 2009Revision History Version Date Changes and/or Modifications 5 November 2009 Updated to latest Gennum template and changed from document number 52023 to 6926. 4 July 2004 Added lead-free and green information. 3 Revisions made. 2 Revisions made. 1 March 1991 New document. Contents Features.................................................................................................................................................................1 Application Selection Chart ...........................................................................................................................1 Description...........................................................................................................................................................1 Revision History .................................................................................................................................................2 1. Pin Connections .............................................................................................................................................3 1.1 Pin Connections ................................................................................................................................3 2. Electrical Characteristics ............................................................................................................................4 2.1 GS1881 Electrical Characteristics ...............................................................................................4 2.2 GS4881 Electrical Characteristics ...............................................................................................5 2.3 GS4981 Electrical Characteristics ...............................................................................................6 2.4 Typical Performance Characteristics .........................................................................................8 3. Temperature Characteristics .................................................................................................................. 11 4. Circuit Description..................................................................................................................................... 14 4.1 Composite Video Input (Pin 2) and Composite Sync Output (Pin 1) ............................. 14 4.2 Back Porch Output (Pin 5) ........................................................................................................... 15 4.3 Vertical Sync Output (Pin 3) ....................................................................................................... 16 4.4 Odd/Even Field Output (Pin 7 GS1881, GS4881) ................................................................ 16 4.5 Horizontal Output (Pin 7 GS4981) ............................................................................................ 17 4.6 Block Diagrams .............................................................................................................................. 17 5. Application Notes....................................................................................................................................... 20 5.1 Choosing the Appropriate Input Capacitor to Optimize Slicing Level and Hum Rejection ....................................................................................................................................... 20 5.2 Filtering ............................................................................................................................................. 22 5.3 Deriving Odd/Even Using the GS4981 ................................................................................... 25 6. Ordering Information................................................................................................................................ 27 6.1 GS1881 Ordering Information .................................................................................................. 27 6.2 GS4881 Ordering Information .................................................................................................. 27 6.3 GS4981 Ordering Information .................................................................................................. 28 GS1881, GS4881, GS4981 Monolithic Video Sync 2 of 29 Separators Data Sheet Proprietary & Confidential 6926 - 5 November 2009